On Fri, 27 Apr 2001 13:35:36 -0000 Martin Roe <[log in to unmask]>
For a description of the Yorkshire alum industry Try : The floating
egg; episodes in the making of Geology by Roger Osbourne. J.Cape 1998
ISBN 0224050281 . An account of cave bones, Jurassic fossils , and how
Alum was extracted .The foating egg refers to the specific gravity of
the liquor when concentrated enough for the egg to float and crystals
of Alum to nucleate and grow ,an be separated form the mother liquor.